Ice making apparatuses of the type mentioned above generally repeat ice making cycles consisting of two types of processes, i.e. an ice making process in which water fed to ice making members is frozen, and an ice releasing process in which the ice making members are warmed by a hot gas and the like after ice is formed on the ice making members so that the ice may be released therefrom. The performance of such ice making process is greatly influenced by ambient conditions, in particular ambient temperature. For example, the thickness of the ice formed in a given period of time is thinner in summer than in winter. The applicant of this invention, therefore, disclosed an ice making apparatus that may automatically controls periods of ice making processes in accordance with ambient temperature so that ice of substantially constant thickness may be manufactured (Japanese Patent Publication No. 59-36175).
Such ice making apparatus as disclosed in the above mentioned publication, however, has a disadvantage that ice may not be made at all or may be made only unsatisfactory if sensors used in the ice making apparatus fails to function normally.